Method for recovering gas generated in a coke oven when charging coal

ABSTRACT

IN A METHOD AND APPARATUS FOR RECOVERING GAS GENERATED IN A COKE OVEN WHEREIN A FLUID IS INJECTED INTO A CONDUIT INTERCONNECTING THE COKE OVEN AND A GAS COLLECTING MAIN, LOW PRESSURE GAS LIQUOR IS INJECTED DURING NORMAL OPERATION OF THE OVEN TO COOL THE GAS, AND HIGH PRESSURE GAS LIQUOR IS INJECTED DURING COAL CHARGING TO DRAW THE GAS IN THE COKE OVEN INTO THE GAS COLLECTING MAIN.

Oct 1973 MINORU YOSHIDA ET m. 3,76

METHOD FOR RECOVERING GAS GENERATED IN A COKE OVEN WHEN CHARGING COALFiled May 28, 1971 FIG.I -4

LOW PRESSURE GAS LIQUOR V J3 a 7 3 2221122? 4 I MINORU YOSHIDA,

MINORU INOUE and SUETOSHI KOIKE,

INVENTORS United States Patent Office Patented Oct. 9, 1973 3,764,482METHOD FOR RECOVERING GAS GENERATED IN A COKE OVEN WHEN CHARGING COALMinoru Yoshida, Minoru Inoue, and Suetoshi Koike,

Kitakyushu, Fukuoka-ken, Japan, assignors to Mitsubishi Kasei KogyoKabushiki Kaisha, also known as Mitsubishi Chemical Industries Limited,Tokyo-to, Japan Continuation-impart of application Ser. No. 38,188, May18, 1970. This application May 28, 1971, Ser. No. 148,146

Int. Cl. C10b 27/04 US. Cl. 201-40 2 Claims ABSTRACT OF THE DISCLOSUREIn a method and apparatus for recovering gas generated in a coke ovenwherein a fluid is injected into a conduit interconnecting the coke ovenand a gas collecting main, low pressure gas liquor is injected duringnormal operation of the oven to cool the gas, and high pressure gasliquor is injected during coal charging to draw the gas in the coke oveninto the gas collecting main.

REFERENCE TO RELATED APPLICATION This application is acontinuation-in-part of our copending application, Ser. No. 38,188,filed May 18, 1970, now abandoned.

BACKGROUND on THE INVENTION This invention relates to a method andapparatus for recovering gas generated in a coke oven while coal or rawmaterial is being charged in the oven.

When charging coal in a coke oven a charging hole of the oven is ventedto the atmosphere so that not only the rich gas generated in the ovenbut also a large quantity of smoke, soot and hot ashes are exhaustedthus resulting in the heavy contamination of air and a fire hazard. Forthis reason, it is necessary to recover the rich gas into a gascollecting main to improve the gas yield and to prevent various publichazards mentioned above.

Various approaches have been proposed in the past to meet thisrequirement. According to one of the approaches an injection nozzle isprovided in a conduit interconnecting the ascension pipe of the cokeoven and a gas collecting main to normally inject washing or coolingwater toward the gas collecting main to wash the gas, and to injectsteam to draw gas and smoke generated in the coke oven and to dischargethem into the gas collecting main. More particularly, as shown in FIG. 1at a bend of a conduit 4 interconnecting an ascension pipe 2 of a cokeoven 1 and a gas collecting main 3 an injection nozzle N is provideddirected toward the gas collecting main. The nozzle N may be a compositetype comprising a central opening through which the water supplied froma water main 5 via a pipe 6 is injected and an annular slit formed tosurround the central opening to inject steam supplied from a steam main7 via a pipe 8.

During the normal operation of the coke oven relatively low pressurewater of about 4 kg./cm. (gauge pressure), for example, is injected intoconduit 4 toward gas collecting main 3 through nozzle N from water main5 to draw out and cool the gas generated in the coke oven 1. However,during the charging of coal into the coke oven, as the water pressure islowered it is impossible to draw out the gas by injecting the lowpressure water as above described. For this reason, during coal chargingin addition to the above described injection of the low pressure water,high pressure steam is injected through the annular slit from steam main7 to provide an injection action to cooperate with the injected water.After the coal charging operation is over injected of steam isinterrupted and thereafter only the low pressure water is injected todraw out and cool the gas generated in the coke oven. These two methodscannot completely eliminate 'the public hazard mentioned hereinabove.Further, they require an expensive high pressure steam generator.

SUMMARY OF THE INVENTION It is an object of this invention to provide animproved method and apparatus for recovering rich gas generated in acoke oven and for preventing public hazard while coal is being chargedin the oven.

Another object of this invention is to provide a novel method andapparatus which can recover rich gas without utilizing steam, thussimplifying the recovering system.

In accordance with the broad aspect of this invention, the gas liquorwhich is formed by distillation and condensation of the water containedin the raw material coal is used not only for the purpose of cooling thegas but also for recovering the gas in the coke oven while it is beingcharged with coal. To this end, it is only necessary to add a simplepump to pressurize the gas liquor to a pressure required for injection.

According to one aspect of the invention, the gas liquor obtained bycondensing the liquid component of the gas generated in a coke oven ispressurized to a high pressure, for example, 6 kg./cm. or more (gaugepressure) by means of a suitable pump and then the high pressure gasliquor is injected through a nozzle provided for a conduit between anascension pipe and a gas collecting main by means of an injector pump, ajet pump for example, whereby to collect or draw out the gas in the oveninto the gas collecting main when charging coal into the oven.

According to another aspect of this invention there is providedapparatus for carrying out the above described method wherein aninjection nozzle is provided at a suitable position of a conduitinterconnecting the ascension pipe and the gas collecting main andconduit means is provided to supply the low pressure gas liquor to thenozzle to cool the gas during the normal operation of the coke oven.Further a pump means is provided to pressurize the low pressure gasliquor to a high pressure, about 6 k'g/cm. (gauge pressure) or more soas to supply the high pressure gas liquor to the nozzle to collect thegas in the coke oven while it is being charged with coal. Valves in theconduits respectively passing the high pressure gas liquor and lowpressure gas liquor may be interlocked so that when one of the valves isopened, the other is closed.

BRIEF DESCRIPTION OF THE DRAWING IFurther objects and advantages of theinvention will be more fully understood from the following detaileddescription when taken in conjunction with the accompanying drawing inwhich:

FIG. 1 is a diagrammatic representation of the prior art apparatusdescribed above and FIG. 2 is a diagram to illustrate a preferredembodiment of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 2illustrating an embodiment of this invention, portions corresponding tothose of FIG. ,1 are designated by the same reference numerals. In thiscase, however, the injection nozzle Na is required to inject only gasliquor so that its construction is more simple than nozzle N shown inFIG. 1 which is required to inject both water and steam. As before, theinner end of the nozzle is directed toward gas collecting main 3. Aconduit 6 including a valve 15 is connected between nozzle Na and a lowpressure gas liquor main 9 which collects water (usually containingammonium) produced by condensing the water component contained in thegas generated in coke oven 1. A pump 10 is provided to pressurize thelow pressure gas liquor in low pressure gas liquor main 9 to a highpressure of about 6 kg./cm. or more, for example. The high pressure gasliquor is supplied to a high pressure gas liquor main 13 from pump 10via conduit 12 and is then supplied to injection nozzle Na via conduit 6and a conduit 14 including a valve 16. Valves 15 and 16 may beinterlocked as shown by dotted line 17 so that when one of the valves isopened the other is closed. Of course it is possible to independentlyoperate valves 15 and 16 alternately.

During normal operation of the coke oven, charging hole H for chargingcoal is of course closed and as it is only necessary to cool gasgenerated in the oven, valve 16 is closed and valve 15 is opened toinject the low pressure gas liquor through the injection nozzle.However, during a coal charging operation as the charging hole H isopened it becomes impossible to draw out the gas in the oven by asuction blower (not shown) connected to gas collecting main 3. Thenvalve 15 is closed and valve 16 is opened to supply the high pressuregas liquor pressurized by pump 10 to injection nozzle Na to createsufficient injection action to drive gas, hot ash and smoke in the cokeoven into the gas collecting main. The ash and smoke are washed andcooled by the injected high pressure gas liquor and are prevented fromescaping into the atmosphere. Moreover, this injection action alsocreates a sufiicient suction in the charging hole H and prevents escapeof smoke and the like into the atmosphere through charging hole H.Although the pressure of the high pressure gas liquor may be above 6 lg./cm. (gauge pressure), preferably from 10 to 25' kg./cm. higherpressures are preferred for larger ovens having a height of 6 or 7meters. However, from the standpoint of economy, it is advantageous tolimit the maximum pressure to about 60 kg./crn. Since supply of the highpressure gas enhances the pumping action of the injection nozzle Na, thegas generated in the coke oven when it is being charged with the coalcan be satisfactorily drawn out into gas collecting main 3. The resultof experiment has demonstrated that there was no appreciable quantity ofgas and smoke issuing into the atmosphere through the charging hole H.After charging of coal, valve 15 is opened while valve 16 is closed toagain inject the low pressure gas liquor, thus resuming the normaloperation.

The method of this invention is advantageous over prior methods in thefollowing points.

(1) As the gas liquor is inherently produced in a large quantity duringcoke production it is more economical than expensive steam ofsubstantial pressure. The only cost involved is the cost of a smallamount of electric power required to inject the gas liquor.

(2) Also the pump for pressurizing gas liquor is less expensive than asteam generator. Further, the injection nozzle is required to injectonly one type of liquid and is not required to inject liquid and steamas in the prior art method so that its construction and the pipingsassociated therewith can be greatly simplified.

(3) When the electric power required to pressurize the gas liquor iscompared with the heat energy of the injected steam on the basis of thework equivalents of heat and electricity, gas liquor is several timesmore "advantageous than steam.

(4) It was actually demonstrated that the power for drawing the gasgenerated in the coke oven into the gas collecting main is unexpectedlylarge.

(5) Scale does not accumulate on the injection nozzle and associatedpipings.

(6) Loss of the available components of the gas generated in the cokeoven in very small so that its quality is not degraded.

(7) Cooling effect for the gas generated in the coke oven is large. i

Thus, this invention provides a novel method and apparatus which caneliminate various defects of the prior art, and which are economical andcan recover the gas generated in the coke oven and prevent publichazardat the time of charging coal into the coke oven.

We claim:

' 1. 'In a method of recovering the gas generated in a coke oven,wherein a fluid is injected through a nozzle into a conduitinterconnecting a coke oven and a gas collecting main, the improvementwhich comprises the steps of injecting a relatively low pressure gasliquor through said injection nozzle during the normal operation of saidoven, said gas liquor being obtained by condensing the liquidcomposition of the gas generated in i said coke oven and injecting saidgas liquor at a higher pressure through said injection nozzle to drawthe gas generated in said coke oven into the gas collecting main whilecoal is being charged in said coke oven.

2. The method as claimed in claim 1 wherein said gas 6 liquor at higherpressure has a pressure higher than 6 l g./cm. (gauge pressure).

References Cited UNITED STATES PATENTS 3,432,396 3/1969 Coleman et al.2012 2,975,109 3/1961 Van Ackeren 202255 X 2,047,283 7/1936 Montgomery202-255 X 1,868,470 7/1932 Forrest et a1 202-255 X FOREIGN PATENTS561,824 11/1957 Belgium 202-255 1,136,980 9/1962 Germany 202255 NORMANYUDKOFF, Primary Examiner D. EDWARDS, Assistant Examiner US. Cl. X.R.202260, 263

